It has turned out that side channel attacks (SCA) and fault attacks are efficient methods for obtaining information about data processed by computing units of electronic devices. This holds in particular for so-called embedded systems, in which the computing unit is connected directly to other functional components of an electronic device, and may be at least partly integrated therein.
Side channel attacks exploit a “leakage”—a function mostly of the processed data—of information from the electronic device or its computing unit that can be acquired in the form of physical parameters and is thus observable by, inter alia, a potential attacker. For example, an electrical consumption of energy, electromagnetic radiation or near fields of the computing unit or of the electronic device, and/or the time of execution of a block cipher by the computing unit can be evaluated during side channel attacks; in this way an attacker can, as a rule, obtain information about data processed by the computing unit, in particular also about secret keys such as those used in the application of cryptographic methods (encryption, decryption, formation of hash values, etc.).
Fault attacks enable the ascertaining of data processed by the computing unit, in particular, again, secret keys used by cryptographic methods, through the targeted introduction of faults (change in the electrical operating voltage, manipulation of clock signals, manipulation of the temperature of the computing unit and/or of the ambient temperature, charging with energy-rich radiation, in particular laser radiation and x-ray radiation) during the processing of the data by the computing unit.